(3-chloro-2-hydroxypropyl)trimethylammonium chloride

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Principles of method if other than guideline:

Detailed data at pH 7.0, 7.8 and 8.4

GLP compliance:

no

Transformation products:

yes

% Recovery:

27.3

pH:

8.4

Temp.:

12 °C

Duration:

357 h

pH:

4

pH:

7

Temp.:

12 °C

DT50:

279 d

pH:

9

pH:

7.8

Temp.:

12 °C

DT50:

21 d

Details on results:

Total recovery derived from following IUCLID4 degradation at pH 8.4 and 12 °C: Degradation (in %): = 72.7 after 357hour(s)

The reaction of CHPTAC in neutral and alkaline pH does not
correctly fit into the definition of hydrolysis but the
reaction is more a conversion reaction.

As the degradation reaction is a reaction of CHPTAC with
OH-ions, the ln c/time plot is not linear and the pH was
decreasing with time. In order to approximate the rate
constants at the given pH values only those values of the ln
c/time plot were used that corresponded to the target
pH-values (pH +-0.1 target pH 7.8 and 8.4). 


pH    kobs [h E-1]  t1/2 [h]

7.0   1.0 x 10 E-4   6700
7.8   1.4 x 10 E-3    505
8.4   5.4 x 10 E-3    127

The major degradation product was EPTAC, minor amounts were
converted to DHPTAC.

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

QUAS020

Radiolabelling:

no

Analytical monitoring:

yes

Transformation products:

not measured

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: The results at 25 °C were calculated from the measured temperatures (50 and 35°C).

pH:

7

Temp.:

25 °C

DT50:

641 h

Remarks on result:

other: The results at 25 °C were calculated from the measured temperatures (50 and 35°C).

pH:

9

Temp.:

25 °C

DT50:

< 1 d

Remarks on result:

other: The results at 25 °C were calculated from the measured temperatures (50 and 35°C).

The results of the preliminary test showed that (3-chloro-2-hydroxypropyl)trimethylammonium chloride is stable at pH 4
(degradation < 10 % after 10 days). At pH 9 the abiotic degradation was > 50 % after 2.4 hours. The main test was only carried out at pH 7.

The results of the preliminary test verify that the hydrolysis reaction is directly influenced by the OH(-)
concentration. Therefore the kinetics of the abiotic degradation of (3-chloro-2-hydroxypropyl)trimethylammonium
chloride is refered to as base catalysed.

k(obs)-values and the corresponding half lifes from the main test at pH 7 and extrapolation to 25 °C:

Test  Temp.  pH 4  t(1/2)  pH7     t(1/2)  pH9   t(1/2)
-----------------------------------------------------------
 1    50 °C  -     -       0.117     6 h   -     -
 2    35 °C  -     -       0.008    90 h   -     -
 *    25 °C  -     > 1 yr  0.001   641 h   -     < 1 d

* extrapolated

The results at 25 °C were calculated from the measured temperatures (50 and 35°C).

Description of key information

The measured half-life of CHPTAC at pH 7.8 and 12 °C was 21 days.

Key value for chemical safety assessment

Half-life for hydrolysis:

21 d

at the temperature of:

12 °C

Additional information

The reaction of CHPTAC with water is more complex than a simple first order hydrolysis reaction. In a standard hydrolysis test conducted according to EC test method C.7 the half-life at 35 °C and pH 7 was 3.75 days. Extrapolating to environmental conditions (12 °C) the corresponding half life is predicted to be 75.5 days. However, other evidence suggested that true reaction rates under neutral conditions were faster than this, therefore a study was performed under environmentally relevant conditions (Raisio, 2004). In this study the measured half-life of CHPTAC at pH 7.8 and 12 °C was 21 days.